Abstract: Objective To assess the efficacy of mecobalamin and glutathione in preventing the neurotoxicity induced by oxaliplatin (L-OHP).Methods A randomized,placebo and control study was made ,in which 9 6 patients with colorectal cancer received L-OHP and 5-Fluorouracil (5-FU)was randomly divided into control group treated with normal saline,mecobalamin group with mecobalamin and glutathione group with glutathione,respectively,32 cases for each.Rate of neurotoxicity and severity was observed by L-OHP-specific neurotoxicity grading and neurological symptom score (NSS).Results Rates of neurotoxicity in control group,mecobalamin group and glutathione group were 90.3%(28 /32),46.7%(14 /32)and 59.4%(19 /32)respectively.After 3-cycle and 6-cycle chemotherapy,the rate of neurotoxicity in degree Ⅱ~Ⅲ was lower in mecobal-amin group than in other groups,but the differences were not significant (P >0.05),whereas NSS score was obviously lower in mecobalamin group than in other groups (P <0.05,P <0.01),but the difference between control group and glutathione group was not significant (P >0.05).Conclu-sion Mecobalamin can prevent the rate and severity of oxaliplatin-induced neurotoxicity.